5 boys were weighed in pairs (two boys weighed together each time). The following results were obtained: 90 kg, 92 kg, 93 kg, 94 kg, 95 kg, 96 kg, 97 kg, 98 kg, 99 kg, 100 kg and 101 kg. What is the total weight of all five boys?
a) 230 kg b) 239 kg c) 240 kg d) 250 kg